The present invention relates to a method for the production of a vitamin-A containing cream primary for skin care.
Vitamin-A is an endogenous compound which occurs naturally in the human body and is essential for normal epithelial cell differentiation. Natural and synthetic vitamin-A derivatives have been used extensively in the treatment of a variety of skin disorders and have been used as skin repair and renewal agents.
The purpose of the invention is to provide a new and improved method for the production of a vitamin-A containing cream which may be used for general skin care and furthermore may be used for preparation of the skin prior to treatment by plastic or cosmetic surgery.
According to the present invention there is provided a method for the production of a vitamin-A containing cream comprising the following steps:
a) a first mixturexe2x80x94consisting of a number of water-soluble substances such as glycerine and extracts of plantsxe2x80x94is mixed together during heating and comminution until the mixture has a temperature of about some 80xc2x0 C., preferably 83xc2x0 C.,
b) a second mixture consisting of a number of oil-soluble substances, including emulsifiers, and squalane and vegetable oils such as avocado oil are mixed together during heating until the mixture has a temperature of about some 80xc2x0 C., preferably 83xc2x0 C.,
c) said first mixture is then gradually added to said second mixture during high-shear-mixing with decreasing number of revolutionsxe2x80x94from about 5000 rpm to about 3300 rpmxe2x80x94until the temperature of the mixture slowly has decreased to about some 50xc2x0 C., preferably 51xc2x0 C.,
d) said last mixture is then added to a third mixture containing of alpha-tocopherol, tocopherol acetate, retinyl palmitate and retinyl acetate preferably in the following mutual relation 10:50:61:58xe2x80x94determined in accordance with the used mixture of vitamines,
e) the final mixture is then successively homogenized at a pressure of about 1000 bar and then kept at constants temperature of some 50xc2x0 C., until the whole mixture is homogenized, whereafter the mixture is high-shear-mixed with decreasing number of revolutions until the temperature is about some 40xc2x0 C., preferable 45xc2x0 C.,
f) finally, the viscosity of the cream is adjusted by stirring.
Tests of the vitamin-A cream produced by the method stated have shown that the very small vitamine-A preparations presumeable due to the high pressure homogenization in combination with the effective shear treatment of the final mixture and due to the presence of the squalanexe2x80x94which itself is an oleaginous substancexe2x80x94are able to penetrate direct into the very small (nmeter sized) oil drops of the oil in water emulsion state of the cream production.
As a consequence this means that the vitamin-A preparations contained in the oil drops of the cream by applying this to the skin in a similar manner due to the presence of the squalane are able to penetrate deeper than the basal cells of the epidermal tissue and act as skin repair and renewal agents.
Preferably by the method according to the invention the content relation between avocado oil and squalene of said second mixture is about 400:500, preferable 425:490.
By the method according to the invention the final mixture after high-pressure-homogenization is high-shear-mixed at a rate of revolution decreasing from about 400-3000 rpm, preferable 3500 rpm, to about 2000-2600 rpm, preferable 2300 rpm.
According to the invention the final adjustment of viscosity of the cream is carried out after some time period of at least about 12 hoursxe2x80x94allowing proper emulsification of the creamxe2x80x94and at room temperature i.e. at a temperature about 20xc2x0-30xc2x0 C.
The present invention furthermore relates to a method of using the vitamin-A containing cream produced by the method according to the invention for the preparation of the skin prior to plastic or cosmetic surgery executed by laser technology and similar surgical treatments, e.g. dermabrasion, by which the outmost possibly wrinkled layers of the epidermal tissue are removed in order to recover a smooth and healthy epidermis wherein the skin area to be treated prior to the surgical treatment is extensively preparated by applying the cream to the skin during a period of time of at least 7-21 days, preferable 14 days, prior to the surgical treatment.
Preferably by the method of use according to the invention the preparation of the skin area to be treated is carried out more times during the day and used also as a night time cream.
In the following the invention is explained in more details by means of a number of examples: